Blade shrouding



Dec. 26, 1944. R c, L N 2,366,142

BLADE SHROUDING Filed July 14, 1943 llllll/Il/A 'IIIIIIIIII A Patented Dec. 26, 1944 BLADE SHROUDING Robert C. AllenyWauwatosa, Wis., assignortto Allis-Chalmers Manufacturing Company, Milwaukee, Wis., a corporation of Delaware Application July 14, 1943, Serial No.-494,644 9Claims. (Cl. 253- 77) This invention relates to turbine blading and has for its object the provision of ashroud construction which can be readily applied to and removedfrom a group of blades without injur or damaging same.

A further object of this invention is to provide an improved shroud construction which canbe readily riveted to a group of tenonless blades.

In accordance with this invention, one or more of the above stated objects may be accomplished in whole or in part by a construction embodying a plurality of blades positioned in passage forming relation and having integral shroud portions presenting opposed contiguous edge surfaces shaped to provide therebetween an enlarged rivet receiving opening, a strip spanning said integral portions and having therein an aperture alined with said opening, and a rivet extending through said aperture and opening for securing said strip to the integral shroud portions on adjacent blades.

The invention accordingly consists of the various details of construction, correlations of elements and arrangements of parts as is more fully set forth in the appended claims and in the detailed description, reference being had to the accompanyingdrawing, in which: I Fig. 1 is a plan View of a partial blade rowembodying the invention; a

Fig. 2 is a partial section taken on line of Fig. 1;

Fig. 3 is a section Fig. 2;

Fig. 4 is a plan view of a partial blade row embodying a modified construction;

Fig. 5 is apartial section taken on line V-V of Fig. 4; and I Fig. 6 is a section taken on line VI-VI ofFig. 5. Referring] to the drawing and particularly to Figs. 1-3, inclusive, it is. seen that apparatus embodying the invention may include a plurality of turbine blades I disposed in passage forming relation and having on adjacent blades integral IIIi shroud portions 2 presenting edge surfaces 3 which are disposed in opposed contiguous or abutting relation and which are grooved or others wise shaped to provide therebetween an enlarged rivet receiving opening 4, a substantially continuous rivet head receiving depression 6 formed in the inner surface of the integral shroud, por-. vtions 2 in surrounding relation about the inner. end of the rivet receivingopening 4, a strip T spanning the integral shroud portions 2 and havin'g therein spaced apertures 8 alined with the rivet receiving openings'l, and rivets 9' which extend throughsaid alined apertures and open-a:

taken .on line III-III of,

ings and have on their inner ends head portions II which extend within the depressions Band act to unite and retain the outer ends of the blades with the edge surfaces 3 on adjacent shroud portions 2 disposed in the opposed contiguous or abutting relation specified when the opposite ends of the rivets are upset or headed to firmly secure the strip 1 to .the substantially continuous outer surface presented by the integral shroud portions 2. 1, l

The strips 1. may bemade plain or provided with one or more sealing flanges I2 as shown and the length of said strips is preferably such that each strip spans'a selected number of blades constituting a group, thereby requiring several blade groups anda corresponding number of strips placed in end to end relation on adjacent groups, asindicated in Fig. 1 in order to form a blade row. The edge surfaces-3 of the integral shroud portions 2 may be grooved or otherwise shaped to formthe rivet receiving openings 4 and, depressions 6 either before or after the blades are positioned in passage-forming relation, and likewise the apertures 8 in strip 1 may be formed either before or after the strip is positioned on the group of'blades to be spanned thereby. A showing of the root ends of the blades has been omitted in the interest of simplicity, as it is immaterial in what manner the blades are mounted on the rotor element carrying same.

The construction just described permits the rivets being readily and uniformly upset or headed-by means of a small rivet press having a C- clamp type anvil positionable between adjacent blades in engagement with the rivet head and a pneumatic-hydraulic force multiplying arrangement operable to apply the same upsetting force to each rivet, thereby eliminating the lack of uniformity andother objectionable eiiects resulting from manually upsetting or peeningover rivets or tenons with a hammer. In addiition, the rivets can be readily removed when position and securec? to the blades by riveting without replacing or altering the blades in any respect. Likewise if only some of the blades in a group, are damaged, only the damaged blades need be replaced since the removal of the rivets and strip does not necessitate altering theremaining blades.

I The aforementioned desirable features and advantages are also present in the modified, construction shown in- Figs.4-6,inclusive, which eming opening l8, a shroud strip l9 spanning the integral shroud portions" and having therein openings 2| receiving the tenons l6 and apertures 22 alined with the rivet receiving openings.

l8, and rivets 23 extending through the alined apertures and openings for securing the shroud strip to the integral shroud. portions I4.

The tenons or projections l6ff un'ction to'unite and retain the outer ends of the blades inftheir proper passage forming relation with the edge surfaces I! on adjacent shroudportions l4 disposed in the opposed contiguous or abutting relation specified. In other words, the tenons I6 and the tenon receiving openings 2| provided on and in the shroud portions and strips l4 and 19, respectively, perform exactly the same retaining function as do the rivet head receiving depressions 6 and the rivet heads H shown in Figs. 1-3. The modified construction shown in Figs. 4-6, inclusive, which may be preferable in that a simple form of rivet can be employed, and that shown in Figs. 1-3, inclusive, can be readily assembled in an obvious manner and a further description in this connection is deemed unnecessary for a complete understanding of the invention. However, both constructions embody blades having integral shroud portions and means including a strip spanning said shroud portions for uniting and retaining the outerends of the blades in their proper passage forming relation;

The invention is applicable generally to elastic fluid turbines embodying blades having integral shroud portions, and it should therefore be understood that it is not intended to limit the invention to the exact details of construction herein shown and described, as various modifications and having therein an aperture-alined with said rivet receiving opening, and-a rivet extending through said aperture and opening for securing said strip to the integral shroud portions on adjacent blades. I

2. In combination, a plurality of turbine blades positioned in passage forming relation and 'embodying a shroud structure comprising integral shroud portions on adjacentblades presenting opposed contiguous edge surfaces shaped to provide therebetween an enlarged rivet receiving opening which extends in a direction approximately normal to "the fluid confiningsurfaceof' said shroud portions, a strip spanning said integral portions and having thereinan aperture alined with said rivet receiving opening, and I means including a rivet extending through said aperture and opening for uniting and retaining the shrouded ends of'adja'centblades with said edge surfaces positioned in opposed contiguous relation. I

3. In combination, a plurality of turbine blades positioned in passage forming relation and embodying a shroud structure comprising integral shroud portions on adjacent blades having outwardly extending projections and opposedcontiguousedge surfaces shaped to provide therebetween an enlarged rivet receiving opening which extends in a direction approximately normal to the fluid confining surfaces of said shroud portions, a strip spanning said integral portions and having therein openings receiving said projections and. an aperture alined with said rivet receiving opening, and a rivet extending through said aperture and opening for securing said strip to the integral shroud portions on adjacent blades.

4. In combination, a plurality of turbine blades positioned in passage forming relation and embodying'av shroud structure comprising integral shroud portions on adjacent blades presenting opposed contiguous edge surfaces. shaped to provide therebetween an enlarged rivet receiving opening which extends in a direction approxie mately normal to the fluid confining surfaces of alined with said rivet receiving opening, means including said strip and integral portions for pcsitioning the shrouded ends of adjacent blades in correct passage forming relation, and a rivet extending through said aperture and opening forsecuring said strip to the integral shroud portions on adjacent blades.

5.. In combination, a plurality of turbine blades positioned in passage forming relation and embodying on adjacent blades integral shroud portions presenting opposed contiguous edgesurfaces shaped to provide therebetween an enlarged rivet receiving opening which extends in a direction approximately. normal to the fluid confining surfaces of said shroud portions, said integral portions having their inner surfaces provided with rivet head receiving recesses disposed adjacent said opening, a strip spanning'saidintegral portions and having an aperture therein alined with said rivet receiving opening, and a rivet extending. through said aperture and, opening and having a head portion disposed in said recesses for uniting and retaining the shrouded ends of adjacent blades with said edge surfaces positioned in contiguous opposed relation.

6. In combination, a plurality of turbine blades positioned in passage forming relation and embodying on adjacent blades integral shroud portions presenting opposed contiguous edge surfaces shaped to provide therebetween an enlarged rivet receiving opening which extends in a direction approximately normal to the fluid confining surfaces ofsaid shroud portions, a strip spanning said integral portions and having an aperture therein alined with said rivet receiving opening, and a rivet extending throughsaid aperture and opening for securing said strip to said integral portions, said rivet and the underside of. saidaintegral shroud portions having contiguous surface portions coacting to unite and retain theshrouded ends of adjacent blades with said edge surfaces'positioned in contiguous opposed relation.

7. In combination, a plurality of turbine blades positioned in passage forming relation and embodying a shroud structure comprising integral shroud portions on adjacent blades presenting abutting edge surfaces grooved to. provide therebetween an enlarged, rivet receiving opening which extends in a direction approximately normal to the fluid confining surfaces of said shroud portion, a strip spanning said integral portions and having therein an aperture alined with said rivet receiving opening, and a rivet extending bodying a shroud structure comprising integral shroud portions on adjacent blades presenting abutting edge, surfaces grooved to provide therebetween an enlarged rivet receiving opening which extends in a direction approximately normal to the fluid confining surfaces of said shroud portion, a strip spanning said integral portions and having therein an aperture alined withisaid rivet receiving opening, and means including a rivet extending through saidaperture and opening for uniting and retaining the shrouded ends shroud portions on adh of adjacent blades'with said edge surfaces positioned in abutting relation. l

9. In combination, a plurality of turbine blades positioned in passage forming relation and. em-

bodying on adjacent blades integral shroud portions presenting abutting edge surfaces grooved to provide therebetween an enlarged rivet receiving opening which extendsin a direction approximately normal to the fluid confining surfaces of said shroud portion, said integral portions having their inner surfaces provided with complementary recesses forming a continuous rivet head receiving depression surrounding said opening,

a strip spanning said integral portions and having an aperture therein alined with said rivetreceiving opening, and a rivet extending through said, aperture and opening and havingtherein a head portion disposed in said depression for uniting and retainingthe shrouded ends of ad- 'jacent blades with said edge surfaces positioned in contiguous opposed relation.

' ROBERT c. ALLEN; 

